Tufted carpet is widely used today in the United States and abroad. Such carpet is produced by tufting machines which are essentially multi-needled sewing machines. The tufting machines push or, more specifically, sew the face yarns of the carpet (also referred to as pile yarns) through a primary backing fabric, forming loops in the face yarns. The machines also hold the face yarns in place while the needles are withdrawn. The resulting loops formed by the face yarns are then either released to form loop-pile, tufted carpet, or cut to form cut-pile, tufted carpet.
A secondary backing fabric, attached to the backstitched side of the primary backing fabric, i.e., the side opposite the protruding face yarns, is used to hold the tufted face yarn in place and is typically attached to the primary backing fabric by a latex or other binding adhesive applied to the backstitched side of the primary backing fabric. Although the combination of the secondary backing fabric and the adhesive binder combine to provide a necessary rigidity to the carpet, allowing it lay flat and resist buckling or travel under use, the back surface of the carpet becomes very rough, indeed abrasive.
Carpet is delivered to installation sites in rolls with the face yarns internal and in lengths from the loom which are usually 12 to 15 feet wide. Because the roll is heavy and somewhat unmanageable, it is frequently dragged around wall corners and through narrow hallways and doorways during which the rough carpet back surface causes damage to the room, house or building in which it is to become installed. Although there are carpets that have a soft backing, such as the foam backing utilized for indoor/outdoor carpet, better quality tufted carpet has typically been produced utilizing the secondary backing and adhesives as described hereinabove. Current tufted carpet production for the year 1997 in the U.S. alone is expected to reach over 4 billion square yards, up from 1.6 billion in 1994. Nevertheless, despite the damage that constantly results from the delivery and installation of carpet, little has been done to change the construction of tufted carpet.
A review of the patent literature over the last three decades, reveals many variations of carpet. U.S. Pat. No. 3,497,414, for instance, discloses a non-woven carpet and method for making the same. The non-woven carpet in the patent is produced by needling a fibrous batt of polyolefin fiber to partially compress and strengthen the batt and to create a smooth face and a pile face from which polyolefin fiber ends slightly protrude. The pile face of the batt is then heated to fuse the fiber ends to form balls on the ends of the fibers. A second batt is placed over the pile face and needled to the first batt. This combination may be employed alone as a carpet or as a carpet topping in combination with a backing which may comprise a needled foam-fiber batt laminate. The backing is preferably composed of polyolefin fiber and a layer of flexible polyurethane foam and is attached to the carpet topping by lamination.
U.S. Pat. No. 3,510,386 discloses the structure of an antistatic carpet that has a fibrous layer, an antistatic conductive coating, and a polymeric backing. The disclosed structure includes a fibrous pile extending upwardly from a primary backing that is initially backed with an antistatic layer. The polymeric backing layer holds the antistatic coating layer in place and may assist the antistatic coating layer in dispersing charges to the ground. The polymeric backing layer is preferably applied in the form of an aqueous dispersion of latex although other polymeric coatings such as polystyrene, vinylidene chloride, polyacrylates, butadiene styrene rubbers and the like may be employed. The patent also discloses that a secondary backing may be optionally applied to the polymeric backing.
U.S. Pat. No. 3,922,454 discloses a secondary backing for carpeting that comprises a woven synthetic scrim with a layer of staple fibers needled onto the top surface of the scrim with portions of the fibers projecting through to the bottom surface of the scrim. A latex coating is then applied to bond the fibers to the bottom surface of the scrim, and the bottom surface is then ironed. The secondary backing is connected to the back side of the primary backing by an adhesive layer. Once applied, the secondary backing provides a non-slip coating which enables the carpet to better frictionally engage the floor.
U.S. Pat. No. 4,112,161 discloses the structure of an indoor/outdoor tufted pile fabric that is intended to be a substantially permanent floor covering. The tufted pile fabric includes a synthetic plastic primary backing and a synthetic plastic secondary backing that are laminated together by a hot melt adhesive to form a relatively rigid impervious sheet. The structure is then provided with a plurality of perforations to give the fabric a softer hand and breathability. The patent intends for the fabric to be adhesively secured to a floor.
U.S. Pat. No. 4,153,749 discloses an antistatic carpet including a primary backing that carries the yarns. A secondary backing includes a base formed of jute or woven or non-woven polypropylene or polyester and a conductive polymeric layer that is bonded to the upper side of the base. The secondary backing is bonded to the primary backing by a conventional non-conductive latex coating layer.
U.S. Pat. No. 4,305,986 discloses a tufted carpeting composed of piled yarns that are anchored in a prime backing that may be either a bonded, non-woven fabric or a woven fabric. A secondary backing is a non-woven fabric composed of individual filaments that are randomly laid out such that they cross over and are bonded at their cross over points with the aid of applications of a secondary binder. The secondary backing is adhered to the primary backing by a rubber or PVC latex coating. The patent discloses that the purpose of the secondary backing is to provide not only better stability to the tufted carpet, but also to provide easy slidability on other surfaces.
U.S. Pat. No. 4,522,857, discloses a carpet tile consisting of a primary carpet base and a foam layer. The carpet base is laminated to the foam layer by an adhesive layer which is embedded with a layer of glass scrim to provide dimensional stability to the carpet tile. The foam layer consists of a fibrous carrier backing of woven polypropylene coated with a high density urethane foam having a tough integral skin surface on its underside. The patent discloses that the carrier backing can be woven or non-woven and composed of other materials such as nylon, polyester or fiberglass. The carrier backing contacts the adhesive that binds the foam layer to the primary carpet base.
U.S. Pat. No. 4,702,950, discloses a carpet tile having a primary backing sheet composed of non-woven polyester or ribbon polypropylene. The carpet tile includes a first precoat composition and a second precoat or intermediate coating composition that includes a limestone filler, a bitumen, petroleum resin and an ethylene vinyl acetate polymer. A second backing coating composition layer includes a bitumen with a thermoplastic rubber polymer material that is bound to a secondary backing sheet that includes a glass fiber scrim material bonded to a secondary backing sheet which forms the exposed back surface of the carpet. The secondary backing sheet may consist, for example, of a non-woven polyester sheet material. The second backing coating is hot melted onto the secondary backing sheet and the combination is laminated to the upper layers.
U.S. Pat. No. 4,871,603, is directed to a carpet tile with a cushioned backing. The backing material is described as being non-woven and is laminated to the carpet base by an adhesive layer, polyolefin, modified polyolefin, polyamide, or other suitable thermoplastic material, which is embedded with a layer of glass scrim to provide dimensional stability. The non-woven layer is about 3/16" to 1/4" in thickness and consists of substantially all synthetic fibers such as polyester, nylon and the like. The patent discloses that the synthetic fibers are held together in the layer by conventional methods of needle punching or air layering.
U.S. Pat. No. 4,988,551, discloses a carpet having a non-woven fleece fabric adhered to a secondary backing by embossing. The non-woven fleece fabric is embossed into a secondary backing that is conventionally attached onto a primary backing. The embossing roll contacts the non-woven fleece fabric and forms high and low areas. The bottom surface of the non-woven layer is then coated with a layer of pressure sensitive adhesive is used to releasably secure the floor covering to an underlying floor. The low areas extend into the secondary backing and serve to unitize the fleece fabric with the secondary backing.
U.S. Pat. No. 5,030,497, is directed to a carpet tile having a hot melt composition backing layer which has a secondary backing of a glass fiber tissue sheet material directly adjacent to a non-woven fibrous sheet material such as a polypropylene sheet material. The secondary backing includes a lightweight, glass fiber tissue sheet material and a spun, bonded polypropylene, non-woven sheet material bonded thereto. The patent discloses that the back surface of the non-woven sheet material is not saturated with any of the hot melt composition that holds the non-woven sheet layer to the glass fiber tissue sheet layer.
U.S. Pat. No. 5,104,712, discloses a surface covering material including an outer layer comprising a preformed fabric, an underlayer comprising a rigid, liquid impermeable sheet material bonded to the underside of the outerlayer by means of an adhesive bonding layer, and a lower layer of a relatively more flexible, hydrophobic closed cell foam that is bonded to the under surface of the under layer by hot melt adhesive or by sintering.
U.S. Pat. No. 5,204,155, discloses a floor covering, such as carpet or carpet tile which includes a primary backing layer composed of a fabric having a fibrous, tufted face and a fibrous back surface which is coated with a pre-coat layer, a first layer, a porous, non-woven glass fiber scrim sheet, a foam layer and a modified bitumen layer. A secondary backing layer includes a porous, glass fiber non-woven tissue sheet material that is directly bonded by the bitumen layer to a non-woven polyester or polypropylene secondary backing layer such that the bitumen layer does not extend through the secondary backing layer.
U.S. Pat. No. 5,470,648, relates to a composite fabric having two layers of non-woven fabric comprising entangled non-bonded nylon filaments and a reinforcing layer of fiberglass scrim adhesively attached to each of the non-woven layers. The composite fabric is useful as a backing in a carpet assembly. The patent discloses that the composite fabric is especially useful in environments where there are seasonal changes in humidity and temperature that cause carpets that are loosely laid to buckle. The non-woven nylon layers are attached to the fiberglass scrim by an adhesive applied to the surface of the scrim.
U.S. Pat. No. 5,540,968, discloses a cushioned backed carpet tile with stabilized non-woven backing. The backing material is preferably a needle punched non-woven material which has undergone a heat treatment to impart a smooth surface finish. The backing material comprises between about 30 percent and about 70 percent polypropylene and between about 70 percent and about 30 percent polyester. The thickness of the backing material can vary in the range from 0.03 inches to about 0.07 inches. A layer of polymer is puddled onto the backing material and doctored to a predetermined height with a blade. The primary carpet fabric is joined with a reinforcement material which is laid directly onto the layer of doctored polymer to laminate the layers.
U.S. Pat. No. 5,558,916, discloses a method for manufacturing a carpet having a secondary backing substantially impervious to liquids. The method involves applying a repellant finish onto the secondary backing material and drying the finish. The finish may be applied as a foam to the secondary backing material which is disclosed as being any of the known backing materials in the art, such as, jute, woven tapes of polypropylene, plain woven polypropylene fabrics, felts, and thermoplastic polymer films. The secondary backing is connected to the primary backing with any suitable adhesive polymeric latex.
U.S. Pat. No. 5,578,357 discloses a carpet having a primary backing with tufts of synthetic carpet fibers protruding from a top surface and, optionally, a secondary backing. The secondary backing is disclosed as being a woven-fiber or non-woven fiber construction. The secondary backing is fused to a sheet of isotactic polyolefin that is fused to the primary backing. The patent also discloses that the bottom layer of the carpet may be formed by a co-extruded layer of thermal plastic polyolefin elastomer fused to she bottom surface of an extruded sheet that is bound to the primary backing.
Finally, U.S. Pat. No. 5,604,009 discloses a non-adhesive bonded carpet comprising primary and secondary backing carpet backing made of non-woven fabrics. The face yarns are tufted into the primary non-woven and then the primary and secondary fabrics are combined without adhesive.
While the art is replete with examples of carpet tiles having a variety of backing materials, the manufacture of broadloom tufted carpet has remained relatively unchanged until the present invention.